When the nearest comet will fly by. The Amateur Astronomer's Guide: Comets
Halley's Comet:
In 1705, Edmond Halley, using Newton's laws of motion, predicted that the comet, which had been observed in 1531, 1607 and 1682, would return in 1758 (which, alas, was after his death). The comet did return as predicted and was later named after him. The average orbital period of Comet Halley around the Sun is 76 years. Its last passage through perihelion was observed in February 1986.
The peak date of the Perseid meteor shower coincides with another astronomical event. During its perihelion, the comet will be about 186 million kilometers away. from the sun. And in the Nenets Autonomous Okrug Rozhen with their telescopes will try to film this comet in order to monitor the processes that occur there.
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Some of them reach such clarity that they are observed even in amateur telescopes. A list of currently available comets can be found, for example, at Seiichi Yoshidi. Comets can be enjoyed and watched as the comet moves slowly between the stars for several tens of minutes. Besides simply enjoying the beauty of the universe, we can also make valuable observations. In comets, so-called clarity assessments are made, which are performed visually. This is where amateur astronomers play a big role.
The nucleus of Comet Halley measures approximately 16 x 8 x 8 kilometers. Contrary to expectations, it is very dark: its albedo is only 0.03, making it even darker than coal. Thus, the nucleus of Comet Halley is one of the darkest objects in the Solar System. The density of the nucleus of Comet Halley is very low, only about 0.1 grams per cubic meter. cm, which suggests that it has a porous structure, since it consists mainly of dust with ice. Halley's Comet will next return to the inner Solar System in 2061.
Thanks to numerous observers from all over the world, it is possible to analyze the behavior of many different comets. When determining the brightness of a comet, it is important that the eye is dark adapted. Astronomers use dark red light when observing, which minimizes dark adaptation.
Another important point- this is where you will observe. It's good to have dark skies. The brighter the sky, the lower the brightness rating. In bright skies, fainter objects are less visible, and the comet will only see the brightest part of it. The fainter outer part of the comet loses itself in the bright sky. This will lead to an underestimation of the comet's clarity.
Comet Hyakutake:
Without exaggeration, we can say that the end of our century is marked by increased interest in cometary research. In 1995, the attention of astronomers around the world was focused on Comet Shoemaker-Levy, which broke up into many fragments and generated gigantic disturbances in the atmosphere of Jupiter after their fall on this planet. The first months of 1996 were marked by the discovery of a new comet - Comet Hyakutake, which for several weeks was one of the brightest objects on the celestial sphere.
Each comet may look different. Some comets are completely scattered, with no signs of brightening in the middle. Others may look like a star. We evaluate the degree of coma condensation using this scale, the scale has 10 values. The degree of condensation is part of the estimate of a comet's brightness.
The degree of cometary condensation Author: Martin Mashek. The size of the telescope must be adapted to the brightness of the comet. There are enough eyes on bright comets. But most comets cannot be seen with the naked eye; we need to use a telescope to observe them.
In contrast to such good famous comets Like Comet Charles XII or Comet Halley, Comet Hyakutake was discovered in January 1996, when it was 300 million km away from Earth. Preliminary data do not exclude the possibility that the previous visit of this comet to the solar system took place 10-20 thousand years ago, but a final answer requires detailed research.
For comets with up to 8 magnets, a classic class is suitable, for example 10 × For even weaker comets, a telescope with a diameter of 200 mm or more is suitable. The clarity of the comet is compared to surrounding stars close to the comet. There are several methods for determining the clarity of a comet. Here are the three main ones.
For all comparative methods, a recording is made that gives an estimate of the brightness of the comet with surrounding reference stars. They are always used with comets of two stars - one fainter than the comet, one brighter. During the assessment, the observer selects what are called evaluative scores. It's good to make an assessment with closer stars.
One of the main features of Comet Hyakutake is the large inclination of its orbit to the ecliptic plane. This determined the extremely favorable conditions for her observations. As it approached Earth, the brightness of the comet constantly increased and on March 23 the comet could be observed even with the naked eye. From March 23 to March 27, 1996, it quickly moved from the constellation Bootes to the constellation Ursa Major and further - to the North Star. At a minimum distance of 17 million km. Comet Hyakutake was away from Earth on March 25, 1996, moving at a speed of 50 km/sec. For the period of 2001, it moves away from the Sun.
During observation, it is good to make a comet plot to the surrounding stars, and the corresponding stars can mark and record scores accordingly. In the observation itself there is no need to know the brightness of the stars with which the comet was compared. The clarity of comparison stars is determined after observation. However, on different planets, the brightness of specific stars may indicate the brightness of stars varying according to the catalog used.
The size of the coma is best determined by drawing a star field around the comet and using a star chart or computer planetarium to determine the comet's size at ambient angular distances. The size of the coma is indicated in arc minutes.
Remnants of Comet Ikeya-Seki:
In October 1965, Comet Ikeya-Seki passed only 450 thousand kilometers from the Sun. Under the influence of harsh solar radiation, the comet's icy core evaporated and lost its constituent gas and dust. During the passage of perihelion (the point of the orbit closest to the Sun), the comet was so bright that it could easily be observed during the day if the Sun was hidden by some structure, or even simply covered by a hand.
Comet tail length and position angle
Sometimes the comet's tail can be observed, usually only brighter. Most faint comets are just hazy specks without a tail. If the tail is visible, its angle and positioning length can be determined. As with determining the size of a comet's comet, it is a good idea to draw a star field around the comet and measure the pony length and position angle using a star chart or computer planetarium. The length of the pendulum is measured in angular degrees. The position angle shows the direction of the comet's tail. North = 0°, east 90°, south 180°, west 270°.
Comet Ikeya-Seki is a member of the Kreutz sungrazers family of comets, named after the German astronomer who studied this family of comets in detail in the nineteenth century. These comets at their perihelion pass less than 50,000 kilometers above the photosphere of the Sun. Most of them are completely destroyed. But few of them, like Comet Ikeya-Seki, are very bright objects.
Determining the clarity of a comet from an assessment
Remember to focus on the telescope image. Determining the position of a comet Author: Martin Mashek. We estimated the relative brightness compared to comparator stars by estimation. It's time to find the clarity of the comet from the estimates. Let's get the clarity of comparison stars from a computer planetarium.
You can also send it in raw form. Observations in Czech Republic collected by the Interplanetary Matter Society, namely Kamil Hornoch. If you need advice, you can also send questions to Jacob Cherny. A simplified observation from observation might look like this.
"Over the course of every century, we've seen 2 or 3 really bright Ikeya-Seki-like objects," says Brian Marsden of the Harvard Center for Astrophysics. "Most of them are fragments giant comets, destroyed at least 2000 years ago. Perhaps a similar phenomenon was observed by the Greek astronomer Ephorus in 372 BC. Ephorus reports that the comet has broken into two parts."
Name and name of the comet Year, month and day, clarity of the comet, size of the decimal point in minutes, degree of condensation, length of the pendulum, instrument used. Observer name, observation location, state name. Recording format - 80 characters. Martin Maszek is a passionate observer of deep sky objects, comets, variable stars and asteroids. Also the discoverer of many variable stars.
This comet is currently visible at low levels outside of urban environments and will become brighter in the coming days. This year is the most profitable income in the last 200 years. Additionally, the comet is known for its unpredictable brightness, which is due to activity at its nucleus.
The size of the comet's nucleus was several kilometers, and now one can observe how remnants several meters in size, when approaching the photosphere of the Sun, flash brightly for short periods of time and disappear in it forever. With the help of the Internet, professional and amateur astronomers can observe these phenomena thanks to the coronagraph installed on board SOHO.
Tuttle, but failed to pinpoint its track, and the comet was lost for decades. He thought it was perfect new comet. However, under unfavorable conditions, she could observe it for only two weeks, and then lost sight of the astronomical instruments.
What was the previous “Czech” comet this year? This comet is known for its unpredictable activity on the surface of its 1.4 km large nucleus, which bounces off large amounts of material in a burst of solar energy. It is accompanied by bright reflections of a comet in the sky.
A coronagraph is a device that blocks the bright light of the Sun so that the Sun's corona and surrounding stars and planets are visible. There are two coronagraphs on board SOHO, one with a 3-degree field of view (“C2” coronagraph) and the other with a 16° field of view (“C3” coronagraph). SOHO is located 1.5 million kilometers from Earth in the direction of the Sun. On the left is an image taken with the C2 coronagraph on April 29, 2000. The circle in the center shows the true size of the Sun.
The comet's brightness is therefore difficult to predict, but this year in early April it may be a naked eye in dark skies at the edge of visibility with clarity around magnitude. If there was a bright rebound, it would be clearly visible without difficulty with the eyes alone. However, it is better to talk about observing the comet with a binocular or smaller astronomical telescope with low magnification and large field review. Clearance of the comet cannot be guaranteed.
Among its most important results are the elucidation of the aging process, the duration of existence and the path of extinction of comets, the discovery and explanation of resonant spaces in the comet system, the determination of the mass of the asteroid system, and the elucidation of the origin of the Tunguz meteorite. He observed comets, asteroids and meteors. . Since mid-March, the comet has been visible all night from central Europe and passes through constellations that rise high at the head in the later hours. It is currently moving through the Great Bear constellation starting in early April, passing through Draco and entering the constellation Hercules at the end of April.
All comets discovered using SOHO images are named "Comet SOHO" and are accompanied by a number indicating the order of discovery. This differs from the traditional naming of newly discovered comet names. The most recent was comet SOHO-143, discovered on July 4, 2000. The official International Astronomical Association designation for this comet is SOHO-143 - C/1998 K15, as the actual images were taken in 1998, and K15 indicates that it was the fifteenth comet found during the second half of May.
In April it will pass through its bed and then it will gradually begin to disappear. The magnitude should be clear in late April and it will be best to see it in the morning when it reappears in the sky at the head. Even in May it will still be within range of the big bells, but it is weakening.
The ideal is a dark sky, without disturbing light sources, far from cities. The sighting has a negative effect on the brightness of the moon, especially around the April full moon. A suitable device is any telescope with low magnification and therefore a large field of view.
Comet Shezo:
The brightest comet of the century - its head was visible during the day. The comet had 6 tails. Perhaps this is a consequence of periodic emissions from the core.
Comet Encke:
It has been observed since 1786. I. Encke calculated the orbit of this comet with the shortest orbital period - 3.3 years. Tunguska meteorite(1908) may have been a fragment of its core. The last approach was in 2000, and the next approach to the Sun will occur in 2004. It is possible that these are the last approaches that can be observed, since the remaining mass of the core is very small.
It's good to have a telescope attached to a simple mounting or photo tripod. The higher the magnification, the greater the shaking of the hand when holding the telescope in the hand. Under the sky, it is good to equip the red light and read the position of the comet on the attached map. Bring your binoculars to a bright star near the comet's current position, then follow the diagram. A foggy cloud with central condensation, called coma, should be visible in the field of view. Don't underestimate the weather outside at night and wear warm clothes.
Abstract: The ground-based astronomical binoculars of the reconnaissance probe and the Hubble binoculars have delivered a lot of information about objects both in the solar system and in the distant universe. The lecture in the first part describes the main bodies moving in our solar system: the Sun, individual planets and small bodies such as comets and asteroids. The second part is devoted to important objects in the distant universe. In addition to stars, it contains star clusters, galaxies, nebulae and some exotic objects.
Comet of 1811:
To this day, it remains the largest-headed: its volume is 6-8 times larger than the Sun.
Comet Donati 1858:
The most beautiful comet of recent centuries. It had well-defined plasma and dust tails. The comet will return in the 39th century.
Great September comet of 1882:
The brightest comet of the century, it was noticed by many at the same time. At its maximum it shone as much as 60 full moons, and during the day it was visible in sunlight. This is one of the “skewing” comets. It flew within the half-radius of the Sun from its surface at a speed of 480 km/s. The core passed in front of the solar disk, but due to its small size it was not visible; after approaching the Sun, it split into two parts. The comet's debris will return around 2650.
Abstract: Information about our objects solar system can be obtained different ways. They could power large ground-based astronomical telescopes, a Hubble telescope in orbit around Earth, or a reconnaissance probe sent to individual sites. The lecture follows the most important and interesting organs of the Solar System. Get basic information about solar activity and learn about the features of some of the planets, their natural satellites, and interplanetary mass, which includes asteroids, comets, and interplanetary dust.
Abstract: The study of objects in the distant universe is carried out mainly using large ground-based astronomical telescopes or space technologies in orbit around the Earth, such as the Hubble Telescope. Some of these materials were a surprise not only to the general public, but also to professionals. Established theories often had to be corrected. The Distance-Space lecture provides the most important information about stars and individual objects that can be observed in the Universe.
1976 Comet West:
One of the most beautiful comets of the century. It had a long, wide tail, reminiscent of a cloud in the rays of the morning Sun. The head glowed like Venus. The comet broke into pieces.
Comet Shoemaker-Levy 9:
In July 1992, the comet passed 15 thousand km. from Jupiter's cloud cover. As a result, the core turned out to be crushed into 17 pieces, stretching over 200 thousand km. In this form, the comet was discovered at the Mount Palomar Observatory by Caroline and Eugene Shoemaker (the best professional comet catchers) and David Levy. The comet did not revolve around the Sun, but around Jupiter with a period of 2 years. During the next approach to Jupiter in July 1994, all the debris crashed into the atmosphere at a speed of 64 km/s. and caused powerful disturbances in cloud cover. The fall was predicted by astronomers and observed from Earth and space.
These include open and spherical clusters, many types of galaxies, nebulae and some exotic objects such as neutron stars, black holes, etc. Abstract: The Sun is our closest star. There are active events inside and on the surface. They occur in the form of sunspots, protrusions, eruptions and other phenomena. How is solar activity cyclical and what are its consequences for planet Earth? You will learn all this in this lecture. The lecture is intended for: all age groups over 12 years old.
Duration of the lecture: about 90 minutes. Abstract: Lecture Crushing Impact concerns the problem of the Earth colliding with celestial body. Even recently, we know of cases when cosmic bodies fell on Earth. Therefore, we are confident that our planet was not spared by these events, like other bodies in the Universe. But are there still dangerous objects that could cause a major cosmic catastrophe? What could happen if the Earth collided with another and bigger cosmic body? Is there a way to disable this?
Since ancient times, people have observed a most beautiful phenomenon in the sky - huge, beautiful comets with tails. It was once believed that the appearance of a comet in the sky was a special type of atmospheric phenomenon. However, in 1577, the Danish astronomer Tycho Brahe refuted this opinion, proving that a comet observed from different points occupies the same position among the stars, which means that the comet is further from the Earth than the Moon.
Halley's Comet
In 1705, Edmund Halley explained the principle of the movement of comets across the sky. According to his calculations, the shapes of the orbits of the comets he observed were close to parabolas. Halley calculated the orbits of the 24 brightest comets, three of which were 1531, 1607 and 1682. have very similar orbits. The astronomer concluded that this is the orbit of the same comet, moving around the Sun in a very elongated ellipse with a period of about 76 years. Halley predicted that it should appear again in 1758, and in December 1758 it was actually discovered. Halley himself did not live to see this time and could not see how brilliantly his prediction was confirmed. This comet (one of the brightest) was named Halley's Comet. Searches for comets were carried out first visually, and then using photographs, but discoveries of comets during visual observations are often made even now. Comets are designated by the names of the people who discovered them. In addition, the newly discovered comet is assigned a preliminary designation based on the year of discovery with the addition of a letter indicating the serial number among the comets found in that year. The preliminary designation is then revised and the letter is replaced by a Roman numeral indicating the sequence of the comet's passage through perihelion in a given year. Only a small part of comets observed annually are periodic, i.e. known but for their previous appearances.
Comet trajectories
The movement of the majority occurs along fairly elongated ellipses, strongly reminiscent of parabolas. Their orbital periods have not yet been determined, they are believed to reach several million years. Many comets move away from the Sun to enormous distances that can be compared to interstellar distances. The planes of their almost parabolic orbits are not concentrated towards the ecliptic plane and are randomly distributed in space. The forward direction of movement occurs as often as the reverse. The orbits of periodic comets are shaped like an elongated ellipse and have completely different characteristics. Of the 40 comets observed more than once, 35 have orbits inclined less than 45º to the ecliptic plane. Only Halley's Comet has an orbit with an inclination greater than 90º, and therefore moves in reverse direction. The rest are moving in a straight direction. Among short-period (i.e., having periods of 3-10 years) comets, the “Jupiter family” stands out - large group comets whose aphelions are the same distance from the Sun as the orbit of Jupiter. It is assumed that the Jupiter family was formed as a result of the planet’s capture of comets that had previously moved in more elongated orbits. The eccentricity of a comet's orbit can increase or decrease depending on the relative position of the comet and Jupiter. In the first case, there is an increase in the period or even a transition to a hyperbolic orbit and the loss of the comet by the Solar System; in the second, a decrease in the period. The orbits of periodic comets are subject to very noticeable changes. Sometimes a comet passes close to the Earth more than once, and then, by the attraction of the giant planets, is thrown into a more distant orbit and becomes unobservable. In other cases, on the contrary, a comet that has never been observed before becomes visible because it passed near Jupiter or Saturn and abruptly changed its orbit. In addition to such abrupt changes, known only for a limited number of objects, the orbits of all comets experience gradual changes. Orbital changes are not the only possible reason disappearance of comets.
rice. Comet Hartley 2 nucleus
Scientists have proven that comets tend to quickly collapse. Short-period comets become less bright over time, and sometimes the destruction process can be observed almost directly. A striking example of such a phenomenon is Comet Biela. It was first discovered in 1772 and then observed in 1815, 1826 and 1832. In 1845, the size of the comet turned out to be noticeably increased, and in January 1846, observers discovered two very close comets instead of one. The relative motions of both comets were calculated, and it turned out that Comet Biela split into two about a year ago, but at first the components were projected on top of each other, and the separation was not immediately noticed. Comet Biela was observed one more time, with one component much weaker than the other, and it could not be found again. But it was observed several times meteor shower, whose orbit coincided with the orbit of Comet Biela.
Why does a comet's tail point away from the sun?
As the comet approaches the Sun, it experiences dramatic changes. Its brightness and tail size increase, and even the structure of the comet itself often changes. The tail of a comet often has the shape of a cone, at the apex of which there is a blurry spot (the head). The head consists of a foggy shell (coma) and a star-shaped core, which is the brightest point of the comet. The brightness of the coma increases towards the nucleus. The heads of comets can be very large - several tens and even hundreds of thousands of kilometers. The tail of a comet is always directed away from the Sun. When the distance from the Sun is great, the tail is absent or very small, only the coma is clearly visible. The rapid development of the comet's tail begins as it approaches the Sun, up to approximately 1 AU. At this time, the tail usually grows at a tremendous speed, about 106 km per day, until it reaches a size of about 108 km. Repulsive forces comet tail from the Sun - this is light pressure and corpuscular flows.
What is the mass of the comet?
The masses of comets are quite difficult to determine, since they are so small that even if they pass close enough to the planets, they cannot affect their movement. Only an upper limit on the mass of comets can be specified. The mass of large comets is about 10,000 times less than the mass of Earth, but in reality the mass can be several orders of magnitude less. It is clear that the average density of cometary matter should also be very low. Coma is a very rarefied gas environment with a molecular concentration of 10 5 -10 10 cm -3. The true, practically invisible core surrounded by this atmosphere, according to modern ideas is a solid body with a diameter of 1 to 30 km. The core consists mainly of volatile substances in the solid state ("ices"), such as CH4, NH3, H2O, CO2. The main ice mass contains molecules of non-volatile substances and their more or less large particles. Approaching the Sun causes the ice to sublimate, releasing gaseous material that forms the comet's tail. At very close distances from the Sun, lines of metals are observed in the spectrum of the nucleus. This proves that, in addition to volatile substances, refractory substances are also present in the nuclei of comets. If the Earth collided with a comet, it would not lead to any catastrophic consequences. The Earth's passage through the comet's tail would only slightly increase the brightness of the sky, but a head-on collision would result in a heavy meteor shower.
Dutch astronomer Jan Hendrik Oort hypothesized that there is a giant cloud of cometary nuclei around the Solar System, which extends to a distance of up to 1 ps. Under the influence of stellar disturbances, the orbits of some nuclei change, as a result of which comets appear near the Sun. On this moment More than 400 short-period comets have been discovered. Of these, about 200 were observed during more than one perihelion passage.